[FFmpeg-cvslog] avcodec/wcmv: check remaining space vs. blocks

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Jun  2 00:08:31 2019 +0200| [dd8720045cdc46536c7a13f091aaf4ddea93e048] | committer: Michael Niedermayer

avcodec/wcmv: check remaining space vs. blocks

Fixes: Timeout (18sec  -> 7sec)
Fixes: 14835/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WCMV_fuzzer-5646714897170432

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=dd8720045cdc46536c7a13f091aaf4ddea93e048
---

 libavcodec/wcmv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/wcmv.c b/libavcodec/wcmv.c
index 2988c15b23..0d60b9fe1f 100644
--- a/libavcodec/wcmv.c
+++ b/libavcodec/wcmv.c
@@ -154,6 +154,9 @@ static int decode_frame(AVCodecContext *avctx,
         bytestream2_seek(&gb, 2, SEEK_SET);
     }
 
+    if (bytestream2_get_bytes_left(&gb) < 8LL * blocks)
+        return AVERROR_INVALIDDATA;
+
     if (s->prev_frame->data[0]) {
         ret = av_frame_copy(frame, s->prev_frame);
         if (ret < 0)